Improvement of an existing high-performance liquid chromatographic (HPLC) technique of analysis of Benzo(a)pyrene (BP) metabolites is being pursued in this laboratory and is being applied to carcinogenesis related problems in collaborative projects to determine the relationship between metabolism and carcinogenicity of Benzo(a)pyrene. Studies involve: (1) evaluation of various commercially available HPLC chromatographic columns for separation and analysis of Benzo(a)pyrene metabolites, (2) optimization of the chromatographic method by using various solvent mixtures and solvent gradient programs, (3) identification of unknown metabolites of Benzo(a)pyrene in activation and metabolism studies by mass spectrometry and (4) applications of high-performance liquid chromatography as an analytical tool for the analysis and determination of metabolites by in vitro metabolic action of different enzyme systems on radioisotope-labelled substrates.